The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
In-vehicle Global Positioning System (GPS) navigation systems are widely used by drivers to determine the location of the vehicle and to provide visual directions to a selected destination. A GPS navigation system utilizes a receiver to receive multiple signals from GPS satellites to determine the current location of the vehicle. Based on the change in location of the vehicle per unit time, the direction and speed of the vehicle may be calculated by the GPS navigation system. The GPS navigation system locates the vehicle on a preloaded map and visually displays a representation of the vehicle on the road of travel, the direction of travel of the vehicle, and the speed of the vehicle. The GPS navigation system may also include an inertia sensor to estimate the speed and direction of the vehicle during brief periods where there may be disruptions in receiving sufficient signals from GPS satellites to determine the location of the vehicle. Such disruptions may be encountered when the vehicle travels through tunnels, parking structures, and certain adverse atmospheric conditions.
While the GPS navigation system is capable of providing the general location of the vehicle on a given road, the GPS navigation system does not provide sufficient fidelity to locate the vehicle within a lane on the given road. Typical commercial GPS navigation systems are accurate to within 15 meters on the average, and more modern GPS navigation systems with Wide Area Augmentation System (WAAS) are accurate to approximately three (3) meters.
While an approximately three (3) meter accuracy may be sufficient to locate a vehicle on a given road for the purpose of providing driving directions, there remains a need to accurately and precisely locate a vehicle within a distinct lane of a road. With the ability of locating the vehicle within a specific lane of travel, the GPS navigation system may provide earlier directions to change lanes in preparation for an upcoming change in direction such as exiting on a highway ramp. Also, the vehicle's Advanced Driver Assistance System (ADAS) may be configured to notify the driver if the vehicle is departing the lane of travel, or host lane, without the intention of the driver, such as when the turn indicator is not activated before a lane change. There is also a need to accurately and precisely locate a vehicle within a lane during prolong periods where there is a disruption or absence of signals from GPS satellites.